Lapping machine



July 25, 1944. w. J. PEI-:Ts 2,354,347

LAPPING MACHINE Filed June 4', 1941 e sheets-sheet 1 Str/rm July 25,1944. w, J, PEE-fs4-` 2,354,347

l LAPPING MACHINE Filed June 4, i941 e s hets-sheet 2 glwumvtom Wilbur J Peet@ July 25, 1944. w. J. PETS 2,354,347

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July 25, 1944. J. PEETS LAPPING MACHINE Filed June 4 1941 6 Sheets-Sheet 4 www,

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LAPPING MACHINE Filed June 4, 1541 s sheets-sheet 5 yJuly 25, 1944. w. J. PEETs LAPPING MACHINE Filed June 4, 1941 6 Sheets-Sheet 6 Patented July 25, 1944 UNITED STATES. Pa'rfieziv'iA oFFicl':l

i IAPPING MACHINE l .l

Wilbur J. Peets, Elizabeth, N. J., assigner to The Singer Manufacturing liaabetil,

N. J., a corporation of New Ierse! l Application June 4, 1941, Serial No.l 396,511

11 (Cl. v.rali-6'!) This invention relates to machines for lapping or grinding surfaces of machine parts which operate in rubbing, sliding or rotative frictlonal contact with other parts and has for its objective the provision of improved means for producing relative movement between the work and the lapping element.

Another object of the invention is to provide improved means for holding the lapping element and moving it into engagement with the work.

Another object of the invention'is to provide a new and improved means for presenting the' cylindrical bore in small bushings and the like to the lapping element.y

Another object of the invention is -to provide improved means for resiliently urging the lapping element into engagement with the surface to be lapped.

.Another object' of the invention is -to provide automatic means for clamping and `rotating the work during the operation of the machine.

A still further object of the invention is to.

provide improved means for quickly stopping the rotation of the work and unclamping it as soon as the lapping operation has been completed.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations, and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a prefered embodiment of the invention, fromwhichl the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art. Y

In the accompanying drawings, Figure 1 is a front elevation of a lapping machine having my invention embodied therein. y

Figure 2 is aside eleva-tion of-the machine shown in Figure 1.

Figure 3 is a vertical sectional view taken through the work-holder and showing its actuating mechanism.

Figure 4 is a section taken along the line 4-4 of Figure 2.

Figure 5 is a section taken substantially along Ythe line 5-5 of Figure 2.

- are journaled the tubular shaft 46 having an en- Company, E

showing the means for controlling the number of reciprocations that will be imparted to the lapping element.

Figures 13 and 14 are front and side elevations, respectively, of the lapping element and Figure 15 is: section taken along the line Il-IS of Figure 1 .In the embodiment of the invention selecte for illustration, my improved lapping machine comprises a frame 2l having a base portion 2| and a head 22. Slidably secured by a dove-tail connection to the base 2l is a plate 23 (Figs. 4 and 5) which is movable up and down relative to the base 2l by means of a hand-wheel 24 fixed to one end of ashaft 25 journaled in the base 2|. To the other end of the shaft 25 there is secured a gear 26 which meshes with a gear 21 xed to a shaft 2l having one of its ends iournaled in a block 29 xedto the base 2l by the screws 30 (Figs. 3 and 5). The shaft 23 is held against endwise movement in the block by the washer 3l which is pinned tothe end of the shaft land the shoulder 32 formed on the shaft, there being a thrust bearing 33 interposed between the block 29 and the shoulder 32. lThe other end of the shaft 28 is formed with a screw-thread which cooperates with a nut 35 ilxed to a bracket 36 which is secured to the plate 23. From the above it will be understood that by rotation of the handwheel 24 the plate 23 may be raised and lowered relative to the frameof the machine.

Slidably carried by the plate 23 is a sub-frame 40 which is confined to a right line movement by the dove-tail connection 4l, with the plate 23 (Figure 4) Formed on the sub-frame 40 are the laterally extending and spaced arms 42 and 43 which carry bm-bearings 44 .and 4l in which larged cup-shaped head 41, the shaft 46 being held against endwise movement in the bearings by means of shoulders formed on the shaft and the nuts 48 and 49. l The shaft 4i is adapted to be rotated atapproximately z500-3000 R. P. M. by means of a.

erally extending arm Il carried yby the sub-frame 40. From the above it will be observed that the shaft 46 and its driving are all carried by the sub-frame 40 vand are movable up and down relative to the frame 20 as a unit.

Fixed by the screws 9| to the top walls off the cup-shaped head 41 is a tubular member 92 having an inclined wall 59 formed on its inner wall. Partially disposed in the tubular member 52 is a chuck 54 having vertical slits 55 in its walls, the outer periphery being formed with an inclined portion which is complemental to the inclined wall 99. From the above it will be understood that when the chuck 94 is forced downwardly the inclined wall 92 will force the walls of the chuck to grip the work. In the present instance the chuck is -designed to externally grip a small cylindrical bushing. The depending reduced .end 95' of the chuck is threaded to receive one end of a pull-rod 99 disposed in the bore of the hollow shaft 49 and having a collar 99 fixed to its other end. The rod 99 passes through a bushing 99 which is carried by the lower end of the shaft 49 and a compression spring 10 reacts 'between the lower end of the bushing 99 and the collar 59 to constantly urge the lower end of the pull-rod 99 downwardly.

The sub-frame 40 is adapted to be moved upwardly and downwardly on the plate 29 by a hydraulic or air piston 1| which actuates a pistonrod 12 having its upper end connected to a lug 19 carried by the sub-frame 40. Fixed to the plate 29 by the screws 15 is a laterally extendving bracket 19 carrying an adjustable stop 11 adapted to be adjusted up and down relative to the bracket by the nuts 19. The stop 11 carries a brake facing of friction material 19 which is engaged by a brake-disk 90 fixed to the lower end of the pull-rod 99. The pull-rod is secured to the shaft 4'9 to rotate therewith by a key 9|` and the up and down movement of the rod |59 is limited vby a stop 92 which is fixed to the shaft 49 by the screws 99 and enters a suitable groove 94 formed in the pull-rod.

Secured to the top of the head 22 is an elecf tric motor 90 having a pulley 9| which drives through a belt 92 a pulley 99 fixed to one end of a shaft 94. A tubular boss 95 is formed on the head 22 and carried by the boss is a bracket 95 in which the shaft 94 is journaled. Secured to the shaft 94 is a worm 91 which meshes with a gear 99 fixed to one end of a shaft 99 Journaled in ball bearings which are carried by the tubular boss 95. To the other end of the shaft 99 there is fixed a crank-disk |0| carrying a. crank-pin |02 which is adjustable as to its eccentricity with the shaft 99 by means of a screw |04. A connecting rod |05 has one of its ends connected to the crank-pin |02 and its other end is connected to the spaced upstanding ears |09 by the wrist-pin |01. The ears |09 are formed on -a sub-frame |09 which has a sliding dove-tail connection with the frame 22 (see Fig. 9). From the above it will be observed that when the motor 90 is operated the frame |09 is reciprocated relative to the head 22 and the amplitude of reciprocation may be varied by the position of the ad- Justabie crank-pin. Also the reciprocation is slow,

i. e. about 25 to 30 reciprocations per minute. due to the worm and gear drive 91 and 98.

Fixed to the frame |09 is a bracket ||0 which carries a motor having a pulley 2 which is operatively connected by a belt I9 to a pulley ||4 fast on a shaft ||5 journaled in bearings ||9 carried by the tubular boss formed on the sub-frame |09. Fixed to the other end of the shaft ||5 is a crank I i9 having a crank-pin ||9 which is embraced by one end 0I Connecting-rod 75 |20 the other end of the connecting-rod being pivotally secured by the wrist-pin |2I to an L-shaped member |22.

Formed on the sub-frame |09 are laterally extending side walls |24 and end walls |25 which form with the frame |09 and end-plate |29 a boxlike enclosure for these operating parts. Slidably journaled in lugs |21 formed at the corners of the boxlike enclosure are guide-rods |29 and |29 which are secured together at their upper ends by the cross-bar |90. To confine the L-shaped member |22 to a right line movement the lower ends of the rods |29 and |29 enter suitable apertures in the member |22 and are clamped therein by any suitable means. herein shown as screws Pivotally mounted in the upstanding limb of the member |22 is a pin |94 having a depending end |35 to which is clamped a carrier ilbhaving a centrally arranged opening which receives a tubular holder or stone carrier |91 which is adjustably secured in the opening by the clamp-screw |99. The holder |91 is provided with a longitudinal aperture (Fig. 6) in which is clamped by the screws |40 the shank of a stone holder |4| which is in the form of a thin rod. The holder .has a groove milled in its face and the corners of the holder in the opposite face are milled out to form the cutouts |42 (Fig. 15). This leaves a relatively thin strip of metal |49 forming the 'back or bottom of the groove. The metal strip |49 at its central point is bent inwardly so that it will engage the rear face of the stone or honing tool |44 at a point equidistant from its ends. This arrangement permits the stone to tilt about the bent strip as an axis and thus align its polishing or lapping face with the surface of the work. I'he strips of metal forming the sides of the groove which receives the stone |44 are also bent inwardly slightly to frictionally engage and hold the stoneinposition.

The carrier |99 is formed with a laterally extending portion |45 apertured to receive an L- shaped rod |41 (Figs. 8 and 9). A tension-spring |49 has one of its ends fixed to the upstanding arm of the rod |41 and its other end fixed by a pin |49 (Fig. l0) to a thimble |50 having its outer surface threaded to receive a disk-shaped nut |52, which i located between the downwardly extending fianges |59 and |54 formed on the bracket |55 which is fixed to the boxlike frame |9|. 'Ihe thimble |50 may be adjusted by the nut |52 to increase or decrease the tension in the spring |49 and a spring-pressed plunger |90 enters one of the depressions formed in one face of the nut |52 to resiliently hold the nut in its adjusted position. A set-screw |9| which enters a groove |92 in the thimble |50 is for the purpose of preventing the thimble from turning.

Formed on the extreme end of the carrier |99 is a lug |94 which is adapted to engage a' collar or stop |95 fixed to the rod |69 which has the end carrying the collar supported byv a bracket |91 fixed to the box |9| which is secured to the frame |09, and its other end pivoted at |99 to a bell-crank lever |69 fixed to a shaft |10 which is journaled in depending ears i1| carried by the box |9|. Also fixed lto the shaft |10 is a lever |19 having a tension-spring |14 fixed toits end. The other end of the tension-spring is adjustably secured to the overhanglng limb |15 of an L-shaped bracket |19 fixed by the screws |11 to the frame |09. From the foregoing it will be understood that the spring |49 constantly urges the carrier |99 to move about its pivotal conassess? 3 nection |84 in a4 clockwise direction as viewed in Figure 9, or to. the left as viewed in Figure 8. 'Ihe spring |14 is stronger than the spring |48 and. consequently. when the machine is not operating the spring |14 urges the lever |18, shaft |18 and bellcrank lever |88 in a clockwise direction. as viewed in Fig. 8. to maintainthe stop or collar |88 in the position shown in Figure 8,

' The initial or inactive position of the carrier |88 and stone |44 can be accurately adjusted so that the stone will enter the bore in the bushing by 1 means of an adjustable stop |88 which is carried at the upper end of an upstanding arm |88' nxed to the carrier |88.

To move the stop |88 out of the way of the lug |84 so that the carriern|88 can swing about its pivot, I have provided a solenoid |80 which is located in and fixed to a suitable box 8| carried by the frame |08. The solenoid is provided with an amature which acts to pull up the rod |82 which is connected to the arm |88 of the bellcrank lever |88 by means of a pin-and-slot connection |84. It will thus be seen-that when the solenoid |80 is energized its armature acts to overcome the spring |14 and shift the bell-crank lever |88 in a clockwise direction thereby permitting'the stone to move to the left, as viewed in Fig. 8, and up against the surface to be lapped.

In order to impart a deilnite'and predetermined number of strokes to the stone |44 and to bring the machine to rest automatically after each piece of work has been lapped, I have formed the hub of the crank disk I| (Fig. 6) with an eccentric |88 which is embraced by one end of a pitman |88 (Fig. i1). The other end of the pitman is pivotally connected to' the arm |81 of a bell-crank lever which is iournaled on asleeve Operation I .The operation of my improved lapping `ma- |88 carried by a stub-shaft |88 which has one of its ends fixed in a bracket |80 secured to the frame of the machine by the screws |8|. Fixed to the sleeve |88 by the screw |82 is a ratchetwheel |88 having a fiat friction spring |84 which bears upon the face of the ratchet-wheel to frictionally hold it in position. Pivotally connected to the end of the arm |88 of the bell-crank lever is a pawl |81 which is adapted to engage the teeth of the ratchet-wheel |88 to advance it step by step when the bell-crank lever is rocked by the pitman 88. Means is provided to cause the pawl |81 to advance the ratchet-wheel by one. two or three teeth andithis means comprises an L-shaped member |88 secured to a hub |88 which embraces the end of the stub-'shaft |88 and is adjustable thereon by the knurled headed screw 200. It will be obvious that the L-shaped member may be adiusted so that on the backward stroke of the arm |88 the pawl will ride upon the` overhanging limb of the L-shaped member toa greater or lesser extent and von its forward stroke -advance the ratchet-wheeleither one or a plurality of teeth for each stroke. Fixed to rotate with the sleeve |88 is a disk 202 having a member 208 secured to its periphery and carried by the member 208 is a roller 204 which is adapted to engage a switch 2108. It will be ob' vious to one skilled in the art that the piston of the cylinder 1| may be actuated either hydraulically or by compressed air and controlled by means of an electrically actuated valve. A separate starter switch button is provided for actuating the valve to cause the piston to rise and the switch 208 is for the purpose of actuating the valve to cause the piston to descend.

react against the collar 88 and actuate the pullrod 88 downwardly thereby causing the chuck 84 to contact and grip the bushing. The movement upwardly of the frame 40 continues until the lapping element |44 extends into the bore in the bushing and at this 'point the stud 208. which is carried by the frame 40, engages the push-button of the electric switch 201 toA close the switch and energize the solenoid and also start the motors 88, 80 and The switch`201 is of the well known type in which the circuit is closed when the button is depressed. and when the button is released it is forced outwardly by .a spring to open the circuit. It will be understood that in the modification shown the stud 208 depresses the button when the sub-frame 40 reaches its extreme upward position and maintains it depressed until the sub-frame 40 begins its downward movement at which time the circuit is opened. v

`'I'he energization. of the solenoid causes its armature to move upwardly and this movement actuates the bell-crank lever |88 against the action of the spring |14, thereby moving the rod 88 to the left. As the rod |88 carries the stop |88, this stop is moved out of the way of the lug |84 which ls formed on the pivoted carrier |36 thereby permitting the carrier to swing about its pivot and carry the lapping stone |44 up against the surface to be lapped. It will be understood that the spring |48 acts to resiliently hold the stone |44 up against the internal surface of the bushing throughout the entire lapping operation. The actuation of the switch 201 also starts the motor 88 andl this motor, through the mechanism above described, rotates the shaft 48 and the work-holder so as to produce a rotary movement of the work relative to the lapping stone |44. The motor 80, which is also started by the switch 201, through the mechanism above described imparts to the frame |08 a reciproatory motion of long amplitude and low vibration,L i. e.,

the stone is caused to move up and down in the the present instance is a small bushing, is rotating at high speed the lapping element is caused to execute a motion in a right line which has both a long vamplitude and low frequencyand a short amplitude and high frequency- The length of time that the work is to be subjected to the lapping operations-can be accuratelyfdeftermined by the counting mechanism which*l has heretofore been described and it will be ,understood that after the roller 204 has made a complete rotation it will actuate the switch205to stop the motors and throw the starting lever to on' position. When this occurs, the hydraulic cylinder 1| acts through the connecting rod 12 to pull the frame downwardly and when the frame a' preaches its lowest position the brakedisk lil, which is iixed to the lower end of the pull-rod Il. engages the friction material 'Il secured to the stop 'I1 ther'eby stopping the rotation of the chuck M and the work. Further downward movement of the frame 4l causes the pullrod Ito be pushed upwardly against the action of the spring 'Iii to open the chuck so that the work may be removed. L

When the switch 20| is actuated the solenoid ist is de-energized and the spring |14 acts through the bell-crank lever arms i" and |13 to pull the rod i and cause the stop i" to engage the lug i on the carrier i and swing the carrier about its pivot to its initial or starting position, as shown in Figure 2.

It will be understood from the foregoing, that, because of the pivotal mounting of the stone i in its carrier, when the stone i engages the wall of the bore in the bushing italigns itself with the surface of the bore and, therefore, the tension of the spring i" is evenly distributed through the entire surface. 'I'his arrangement serves to present the entire working face of the stone tothe surface and produces a uniform lapping of the work.

It will be observed that the lapping element is reciprocated in a vertical plane and the article or work is rotated about a vertical axis. This construction results in a machine which is com- Pact. requireslittle floor space, and which is readily accessible for the purpose of inspection, cleaning and repair.

It will also be understood that the throw of the crank-pin |02 may be adjusted to vary the up and down movement of the lapping element relative to the article being finished. Also the position of the article may be varied relative to lthe lapping element by means of the hand-wheel 24. This permits the article to be adjusted so that any selected portion of the article will receive more or less of the lapping operation.

From the foregoing description considered in.

connection with the accompanying drawings. the construction, manner ofoperation and several advantages of my improved lapping machine will be clearly and fully understood. Itis apparent that such a machine has a wide variety of uses,

and it will be understood that the formgconstruction and arrangement of the elements employed may be varied. Therefore, the privilege is reserved of resorting to all such legitimate changes therein as may be fairly embodied within the spirit and scope of the appended claims.

Having thus set forth the nature of the invention, what I claim herein is:

1. Lapping apparatus including amain frame, a sub-frame slidable on said frame and confined to a Vright line movement, means for reciprocating said sub-frame, a driving device carried by said sub-frame and operatively connected to rotate an eccentric element, a member operatively connected to and vibrated by said eccentric element, a stone holder pivotally mounted on said member, a spring for urging said holder` about its pivot, an abrading stone mounted in said holder for pivotal movement relative thereto, a work-holder carried by said main frame, means for moving said work-holder toward said lapping element and means for rotating said work-holder.

2. Lapping apparatus including. a main frame, a lapping element carried by said frame and supported for movement about a vertical pivot.

'ass-asn means for concurrently imparting to said lapping element a reciprocatory motion of long amplitude and low frequency and a reciprocatory motion of short amplitude and high frequency, said motion being in a right line, and in a vertical plane a work-holder adapted to hold a piece of work having an internal cylindrical wall, means for moving the work-holder towards the lapping element, resilient means for urging said lapping element about its pivot and into engagement with the internal wall of the work, means for rotating said work-holder. means for moving the workholder away from the lapping element at the completion of the lapping operation, and means for arresting the rotation of the work-holder after it has been moved away from the lapping element.' l

3. Lapping apparatus including Vmeans for holding an article to be finished. means for rotating said article-holding means, a lapping element, mechanism for imparting a reciprocatory motion of long amplitude and low frequency to said lapping element and also imparting a reciprocatory motion of short amplitude and high frequency to said lapping element, said motions being concurrent and in a right line, means for presenting the surface of said article to said vlapping element automatic means for moving said lapping element out of contact with the article at the completion of the lapping operation,

land means for arresting the `rotation of the work-holding means at the completion of the lapping operation.

4. Lapping apparatus including means for holding an article having an internal cylindrical surface, means for rotating said work-holding means, a pivoted lapping element, mechanism for imparting a reciprocatory motion of long ampliand also imparting a reciprocatory motion of short amplitude and high frequency to said lapping element, said motion being concurrent and in a right line, means for presenting the internal surface of said article to said stone, spring means for moving saidstone into contact with said surface of the article, and means for arresting the rotation of the work-holding means at the completion of the lapping operation.

5. Lapping apparatus including means for holding an article having an internal surface, means for rotating said work-holding meanaa lapping element, mechanism for imparting a reciprocatory motion of long amplitude and low frequency to said lapping element and also imparting a reciprocatory motion of short amplitude'and high frequency to said lapping element, said motion being concurrent and in the same plane, means .for presenting the internal surface .of said article to said stone, spring means for maintaining said stone in contact with said surface of th article, means for arresting the rotation of the work-holding means at the completion of the lapping operation, and automatic means for reasing the work from the work-holder.

6. Lapping apparatus including means for holding an article having a cylindrical internal bore. a lapping element in the form of a bar which is smaller than the internal bore in the article, means for mounting said lapping element for movement about horizontal and vertical axes, mechanism for imparting longitudinal reciprocatory movements to said element and concurrently vibrating said element in vertical plane, means for moving said article holder relatively to the lapping element so that the lapping element enters the" bore in the article, automatic means for moving the lapping element about its vertical pivot into engagement with the wall oi.' the in-` mechanism for imparting longitudinal reciprocatory movements to said element and concurrently vibrating said element in vertical plane, means for moving said article holder relatively to the lapping element so that the lapping element enters the bore inV the article. automaticv means ior moving the lapping element about its vertical pivot into engagement with the wall ot ping element, a movable stop for holding said stone holder against the action of said spring .and in a position so that the lapping element enters the bore in the article, and automatic means under control of said work holder for shifting said stop toxrelease said holder and permit said vspring to move the lapping element into engagement with the surface of the bore in the work.

Lapping apparatus including a main frame, a sub-frame slidable on said main trame and conilned to a right line movement, mechanism for imparting a longitudinally reciprocatory movement to said sub-frame, a member carried by said sub-frame, mechanism mounted on said sub-frame i'or imparting a vibratory motion to said member, a stone holder pivotally secured to said member, spring means for moving said holder about said pivot, a work holder for holding a tubular article having a cylindrical bore, means i'or movingsaid work holder towards thelapping element,"a movable stop for holding saidv stone holder against the action oi' said spring and in the bore in the article at the beginning of the lapping operation, automatic means for moving the lapping element out oi' engagement with said wall at the completion ot the lapping operation, and means for rotating the work relative to the lapping element.

8. Lapping apparatus including means for holding an article having an internal cylindrical bore, a lapping element which is smaller than the internal bore in the article, means for mounting said lapping element for movement about a vertical axis, mechanism for imparting longitudinal reciprocatory movements to said lapping elementand concurrently vibrating said elemnt in a vertical plane. mechanism for moving said article holder relative to the lapping element so that the lapping element enters thebore in the article, means for rotating said article holder, spring means for moving the lapping element about its vertical pivot into engagement with the wall of the internal bore in the article after the lapping element has entered the boe thereoiI and automatic means for moving the lappins element out o! engagement with the article at the completion 0f the lappina peration.

9. Lapping apparatus including a main trame, a sub-trame slidable on said main frame and coniined to a right line movement, mechanism ior imparting a longitudinally reciprocatory movement to said sub-frame, a member carried by said sub-frame, mechanism mounted on said subiramo for imparting a vibratory motion to said member, a stone holder pivotally secured to said member, spring means tor moving said stone holder about said pivot, a work holder i'orhclding atubulararticlehavingacylindrical borameans for moving' said work holder towards the lap- 'a position so that the lapping element enters the bore in the article, automatic means for shii'ting said\ stop to permit said spring to move said lapping element into engagement with the surface of the bore, and means to move the lapping element away from the work at the completion of the lapping operation.

11. lapping apparatus including a main frame, a sub-frame lslidable on said main framel and confined to a right line movementl actuating mechanism'for imparting a reciprocatory movement to said sub-frame, a member carried by said sub-frame, a second actuating mechanism mounted on said sub-frame i'or imparting a vibratory motion to said member, a 'stone holder pivotally secured to said member, spring means for urging said stone holder about said pivot, a movable stop for holding said stone 'holder against the action oi said spring and in a predetermined position, a lapping element pivotally secured Vintermediate its ends to said holder, a second subirame carried by said main frame, a work holder adapted to hold a tubular piece oi work having an internal cylindrical bore and carried by said second sub-frame, means for imparting a rotary motion to said work holder whereby the work will be rotated relative to the lapping element, means for moving said sub-frame towards said lapping element to cause the lapping element to enter the bore inthe work and automatic means eilective when said second sub-trame has reached a predetermined position for moving the stop so that the stone holder will swing about its pivot andthe lapping element will be spring urged into engagement with the work.

wnmnw. rms. 

